Islamic State (Isis) has claimed responsibility on 23 July for a suicide car bombing in a Baghdad district that killed at least 20 people the day before.
In a statement posted online, the Sunni militant group said it had targeted a security checkpoint in the al-Shurta al-Rabaa neighbourhood of the mainly Shi'ite district.
A further 48 people were wounded by the blast, which damaged shops and restaurants.
IS had also claimed responsibility for a massive blast that killed more than 100 people less than a week ago in Khan Bani Saad.
Iraqi security forces and Shi'ite paramilitary groups are currently focused on the western province of Anbar, where they have been gearing up for an offensive to retake the mainly Sunni Muslim governorate – Iraq's largest.